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OnePlus 9 Battery review: Excellent charging

Reading Time: 5 min read
77
battery
Charging Time
2 days 6h
Battery life
Charging Time
0h21
80% Charging time
Charging Time
0h39
Full charging time

Released in March 2021, the OnePlus 9’s launch price places it in the Premium ($600-$799) segment. As such, it comes packed with many attractive features, including a powerful Qualcomm Snapdragon processor and stereo speakers with Dolby Atmos. Our engineers put the OnePlus 9 through our Battery protocol tests; here is a summary of the results.

Key specifications:

  • Battery capacity: 4500 mAh
  • 65W charger
  • 15W wireless charging
  • 6.55-inch, 1080 x 2400, 120 Hz AMOLED display
  • Qualcomm Snapdragon 888 5G (5 nm) chipset
  • Tested RAM / storage combination: 8 GB + 128 GB

About DXOMARK Battery tests: For scoring and analysis in our smartphone battery reviews, DXOMARK engineers perform a variety of objective tests over a week-long period both indoors and outdoors. This article highlights the most important results of our testing. (See our introductory and how we test articles for more details about our smartphone Battery protocol.)

Test summary

OnePlus 9
77
battery
56
autonomy
104
charging
78
efficiency

Pros

  • Two full days of autonomy with moderate use, best in its segment
  • One of the best charging times in our database to date
  • Decent on the go performance, best in its segment

Cons

  • High consumption during video playback
  • Falls short in efficiency

The OnePlus 9 provides a decent performance for a device in its price range, and sits squarely in the top half of our database. The Oppo Find X3 Neo beats the OnePlus by 4 points, thanks to its better autonomy and efficiency scores, but the OnePlus comes in above both the Xiaomi Mi 11 and the Samsung Galaxy S21 5G (Snapdragon). We compared the OnePlus 9’s performance in several key categories with these other three Premium-segment devices;  battery capacity, charger, display type and resolution, and processor specifications for all four smartphones are shown in the table below.

OnePlus 9

Oppo Find X3 Neo Xiaomi Mi 11

Samsung Galaxy S21 5G (Snapdragon)

Battery capacity 4500 4500 4600 4000
Charger 65W 65W 55W 25W
Wireless 15W No 50W 15W
Display type OLED OLED OLED OLED
Display resolution 1080 x 2400 1080 x 2400 1440 x 3200 1080 x 2400
Chipset Qualcomm Snapdragon 888 5G Qualcomm Snapdragon 865 5G Qualcomm Snapdragon 888 5G Qualcomm Snapdragon 888 5G

Autonomy (56)

How long a battery charge lasts depends not only on battery capacity, but also other aspects of the phone’s hardware and software. The DXOMARK Battery autonomy score is composed of three performance sub-scores: (1) Stationary, (2) On the go, and (3) Calibrated use cases. Each sub-score comprises the results of a comprehensive range of tests for measuring autonomy in all kinds of real-life scenarios.

Light Usage
76h
Light
Active: 2h30/day
Moderate Usage
54h
Moderate
Active: 4h/day
Intense Usage
34h
Intense
Active: 7h/day

The OnePlus 9 comes in just behind the currently class-leading Oppo Find X3 Neo in the rankings of premium devices, and just edges out the Samsung. All three devices are far ahead of the Xiaomi Mi 11 (whose display in fairness has more pixels to handle).

The battery gauge on the OnePlus 9 accurately displays how much power remains.

Stationary

OnePlus 9

59

104

Vivo Y72 5G
Best: Vivo Y72 5G (104)

A robot housed in a Faraday cage performs a set of touch-based user actions during what we call our “typical usage scenario” (TUS) — making calls, video streaming, etc. — 4 hours of active use over the course of a 16-hour period, plus 8 hours of “sleep.” The robot repeats this set of actions every day until the device runs out of power. 

The OnePlus 9 lasted 57 hours 24 minutes in our TUS tests, which is 1 hour 37 minutes less than the Oppo; the Xiaomi and the Samsung lasted 40 hours 05 minutes and 56 hours 22 minutes, respectively.

This means you can expect more than two full days of autonomy with the OnePlus 9 with average use. The OnePlus’s night management could have been better: the device loses 2.33% on average, while the Samsung and the Oppo lost 2%.

Typical Usage Scenario discharge curves

On the go

OnePlus 9

58

96

Samsung Galaxy M51
Best: Samsung Galaxy M51 (96)

Using a smartphone on the go takes a toll on autonomy because of extra “hidden” demands, such as the continuous signaling associated with cellphone network selection, for example. DXOMARK Battery experts take the phone outside and perform a precisely defined set of activities while following the same three-hour travel itinerary for each device.

The OnePlus 9 posts the best score among its rivals in this review, with particularly good measurements for camera use and social apps compared to its rivals.

Estimated autonomy for on the go use cases (full charge)

Calibrated

OnePlus 9

58

100

Samsung Galaxy M51
Best: Samsung Galaxy M51 (100)

For this series of tests, the smartphone returns to the Faraday cage and our robots repeatedly perform actions linked to one specific use case (such as gaming, video streaming, etc.) at a time. Starting from an 80% charge, all devices are tested until they have expended at least 5% of their battery power.

With a score of 63, the Oppo Find X3 Neo did a better job than the OnePlus 9, especially during the video playback, where the OnePlus device put in a poor showing. In other use cases, however, the two devices are very similar, and both best the Xiaomi and the Samsung in almost all use cases.

Estimated autonomy for calibrated use cases (full charge)

Charging (104)

The DXOMARK Battery charging score is composed of two sub-scores, Full charge and Quick boost. Full charge tests assess the reliability of the battery power gauge; measure how long it takes to charge a battery from 0% to 80% capacity and from 80% to 100%; and measure how long and how much power the battery takes to go from an indicated 100% to an actual full charge. With the phone at different charge levels (20%, 40%, 60%, 80%), Quick boost tests measure the amount of charge the battery receives after being plugged in for 5 minutes. 

Wired
Wired
96%
in 30 min
0h21
0 - 80%
0h39
Full charge
Wireless
Wireless
27%
in 30 min
1h28
0 - 80%
1h57
Full charge

A strong performance with its 65W charger puts the OnePlus 9 in first place in our ranking across our entire Battery protocol database to date, with the Oppo Find X3 Neo and its 65W charger slightly behind at 101. The Xiaomi and the Samsung are far behind (which is no great surprise, at least with respect to the Samsung, given its 25W charger).

Full charge

OnePlus 9

106

Highest Score

Power consumption and battery level during full charge

The OnePlus 9 goes from empty to a full charge in only 38 minutes 40 seconds, and takes only 21 minutes 22 seconds to go from 0 to 80%, which is truly impressive. The Oppo does a great job going from 0 to 80%, too, taking just 22 minutes 57 seconds.

Time to full charge

The OnePlus 9 comes with a 55W wireless charger, but the smartphone supports only 15W wireless charging, drawing in only 10.7W on average; this results in a wireless charging time of 1 hour 57 seconds to achieve a full charge. By way of comparison, while the Xiaomi Mi 11 comes with a 50W charger, but its peak output is 36W and its average output is 22.8W, so its wireless charging time is 1 hour 14 minutes. Coming with a 15W wireless charger (with average output of 10.7W) and a smaller battery to fill, the Samsung takes 2 hours 40 minutes to reach a full charge.

Quick boost

OnePlus 9

94

108

Oppo Reno6 5G
Best: Oppo Reno6 5G (108)

With a five-minute charge at 20%, the OnePlus 9 can provide almost 8.5 additional hours, which is huge — one of the very best results in our database.

OnePlus 9 Oppo Find X3 Neo Xiaomi Mi 11 Samsung Galaxy S21 5G (Snapdragon)
Autonomy boost (hh:mm) 20%8:26 8:20 2:52 2:38
40%5:59 6:26 3:09 2:45
60%5:28 5:29 2:54 2:09
80%4:02 4:14 1:51 1:57
Percentage boost 20%23 %22.1 %11.2 %7.4 %
40%16.3 %17 %12.3 %7.7 %
60%14.9 %14.5 %11.3 %6 %
80%11 %11.2 %7.3 %5.5 %
Energy consumed 20%4923 mWh4712 mWh2674 mWh1466 mWh
40%3491 mWh3637 mWh2945 mWh1528 mWh
60%3188 mWh3103 mWh2709 mWh1195 mWh
80%2354 mWh2399 mWh1735 mWh1088 mWh

Efficiency (78)

Our Efficiency score comprises two sub-scores, Charge up and Discharge. Charge up is the efficiency of a full charge (how much energy is drained from the wall outlet vs the energy capacity of the battery, as well as the efficiency of the charger and its residual consumption). Discharge is how much current the smartphone drains from the battery when in use (the ratio of battery capacity to autonomy). Better autonomy with a smaller battery means better efficiency.

Efficiency is not the OnePlus 9’s strongest point: despite the best charge up score to date, its discharge score is just average, so overall among the four devices in this comparison, it comes in third.

Charge up

OnePlus 9

84

Highest Score

The OnePlus 9 has the most efficient charger among tested devices to date, and thus the top score for this attribute, but its residual consumption when the smartphone is plugged in is high.

Discharge

OnePlus 9

74

121

Apple iPhone 13
Best: Apple iPhone 13 (121)

The OnePlus 9 earns an average score in our database for discharge efficiency. The Samsung with its 4000 mAh battery puts in a good performance and achieves a score of 90; thanks to its fairly good decent results and its well-managed night discharge, the Oppo achieves an 85.

Thanks to well-controlled discharge current during use and well-managed night discharge, the Oppo achieves an 85. By contrast, the Xiaomi struggles here with much higher discharge current when used with its QHD display on.

Conclusion

The OnePlus 9 puts in a great performance for its price range, with two full days of autonomy, decent on the go results, and an especially impressive charger.

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